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Biomedical subjects

J Newman

Publications and source records attributed to J Newman.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Hepatitis B virus, hepatitis non-A, non-B virus and hepatitis delta virus in lyophilized antihemophilic factor: relative sensitivity to heat.

Lyophilized plasma derivatives are more stable to heat than when they are in the liquid state. Commercial Factor VIII (antihemophilic factor) was seeded with a measured quantity of hepatitis B virus. The contaminated material was then lyophilized and subjected to heat of 60 degrees C for 30 hr. Chimpanzees were inoculated with the heat-treated antihemophilic factor or sham-treated antihemophilic factor that had been held at 4 degrees C. Surprisingly, hepatitis B virus survived the heating procedure with no apparent loss in titer: the incubation period to appearance of HBsAg was that expected for the challenge dose of virus. Even more surprising, one chimpanzee (the recipient of the unheated antihemophilic factor) also developed non-A, non-B hepatitis and two chimpanzees (recipients of the heated antihemophilic factor) also developed delta hepatitis. Neither of these agents was a contaminant of the hepatitis B virus challenge pool, since the purity of this hepatitis B virus pool was established previously in chimpanzees. Thus, both a non-A, non-B agent and the delta agent apparently contaminated the commercial antihemophilic factor. This is the first direct evidence for contamination of antihemophilic factor with the delta agent and confirms previous seroepidemiologic evidence for its presence in pooled plasma derivatives. Subsequent inactivation studies were performed with antihemophilic factor experimentally contaminated with the Hutchinson strain of non-A, non-B hepatitis virus. In these studies, heating at 60 degrees C for 30 hr in the dry state rendered antihemophilic factor free of detectable non-A, non-B hepatitis virus.

Animals↗
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Improved lensometry with a programmed calculator-lensometer combination.

The arithmetic associated with prescription calculation seems to be the major source of error and inefficiency in the performance of traditional lensometry. We have found that a programmed calculator used in combination with a lensometer achieves greater accuracy in less time than does the lensometer alone. This approach may be a useful alternative to the physician who does not wish to make a substantial investment in a fully automatic device.

Computers↗
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Repeat dilation of Palmaz stents in pulmonary arteries: study of safety and effectiveness in a growing animal model.

PURPOSE: This study assessed the technical feasibility and safety of repeat dilation of Palmaz stents in growing pulmonary arteries. MATERIALS AND METHODS: Palmaz stents (1.2 cm long) were placed percutaneously into the pulmonary arteries of 20 newborn lambs. After 4 months, pulmonary arteriography was performed. Where vessel growth in excess of stent diameter had created a stenosis (> 15%), stents were dilated again percutaneously. Six months later, pulmonary arteriography was performed, before the animal was killed and histologic examination performed. RESULTS: Twenty-four pulmonary artery stent placements were attempted; 23 were successful. One stent placement was unsuccessful owing to stent displacement from the balloon. Acute complications included branch pulmonary artery occlusion (n = 3) and stent displacement from the delivery balloon (n = 2). At 4 months, the desired degree of stenosis (> 15%) was achieved in 11 animals. The average stenosis was 35% (standard deviation, 16%; range, 17%-66%). The mean predilation stent diameter was 6 mm +/- 1.1 (range, 4-8 mm), and the final diameter of 8 mm +/- 1.4 (range, 6-10 mm), represented a 35% mean increase (P < .001). Complications included stent (n = 1) and branch vessel (n = 1) thrombosis. At 6-month follow-up, all stents were patent. Areas of previously noted branch thrombosis were fully recanalized in all cases. At histologic inspection, only a thin layer of neointima was found on the stents. CONCLUSION: Repeat dilation of Palmaz stents may be safely performed in growing pulmonary arteries in an animal model. Neointimal hyperplasia is minimal in pulmonary artery stents.

Animals↗
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Prehospital identification of acute coronary ischemia using a troponin T rapid assay.

OBJECTIVE: To evaluate the performance of a rapid assay for cardiac troponin T (cTn-T) in patients with chest pain in the prehospital setting. METHODS: A prospective, observational clinical trial in a rural county served by a single emergency medical services system and two emergency departments. Patients fulfilling prehospital criteria to identify acute coronary ischemia (ACI) had a blood sample applied to the cTn-T rapid-assay device. Quantitative analysis of cTn-T was also performed on each sample at a later time. Medical records were reviewed to determine ultimate diagnoses. Non-admitted patients were followed by telephone at one week. Main outcome measures included the sensitivity, specificity, positive predictive value, and negative predictive value of the rapid cTn-T assay for detecting ACI defined as acute myocardial infarction (AMI) or unstable angina (UA) within one week of presentation. RESULTS: Of 87 patients enrolled, 29 were identified with ACI. This included 15 patients diagnosed as having AMI and 14 patients diagnosed as having UA. The cTn-T rapid-assay device was positive for five of 87 patients (5.7%); three were associated with AMI and two with UA. Measurement of a single cTn-T to detect ACI had a sensitivity of 17.2% (0.058, 0.358), specificity of 100% (0.950, 1), positive predictive value of 100% (0.549, 1), and negative predictive value of 70.7% (0.609, 0.806). CONCLUSION: The cTn-T rapid-assay device may be useful in the prehospital setting to identify a small number of patients with ACI. The authors caution, however, that a negative test in the prehospital setting cannot be used to rule out significant disease.

Acute Disease↗
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Factors associated with Medicare beneficiary complaints about quality of care.

This article examines the number and types of formal complaints about quality of care that were made by Medicare beneficiaries and submitted to the California Peer Review Organization (PRO) during the period July 1, 1995-December 30, 1996. Logistic regression models were used to analyze the complaints in terms of sociodemographic factors, enabling factors (income and health maintenance organization [HMO] membership), diagnoses, and primary service providers. The complaint rate was found to be very low, and only 13% of complaints were confirmed by the PRO. HMO members and members receiving physician care and outpatient/emergency room care were more likely to complain about denials of or delays in services or the failure to be referred to specialists than were members in fee-for-service plans and those receiving other types of provider care. Complaints about poor nursing care were associated with receiving skilled nursing/rehabilitation care. Complaints about care that resulted in injury were associated with the denial of care, failure to be referred to a specialist, poor medical care, and poor communications. Complaints about care that led to disability were associated with medical errors, whereas those that led to death were associated with misdiagnosis and premature hospital discharge. It would be valuable for PROs to focus their complaint review efforts on common types of complaints in different settings. A review of PRO procedures should be undertaken to understand why so few complaints are submitted and confirmed.

Aged↗
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Preventing fungal infections in immunocompromised patients.

The incidence of systemic fungal infections in immunosuppressed patients has increased in the past two decades (Fridkin and Jarvis, 1996). Bone marrow transplant recipients and patients with prolonged neutropenia are most at risk, particularly when environmental factors increase the presence of fungi and fungal spores. Preventive measures include air filtration, handwashing, exclusion of flowers and some foodstuffs and use of chemoprophylaxis. In April 1999, a meeting was held under the auspices of the European Group for Blood and Marrow Transplantation (UK) Nurses and Allied Professionals Group to discuss the role of nurses in the management of patients at risk of systemic fungal infection. Issues discussed included: the need for nurses to recognize risk factors for systemic fungal infection; the role of nurses in giving feedback to patients; and the use of antifungal agents and associated problems, such as non-compliance and side-effects.

Bone Marrow Transplantation↗
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MQSA: the final rule.

On April 28, 1999, the final Mammography Quality Standards Act (MQSA) rule takes effect. On that date, the final regulations will replace the interim standards that have been in effect since October 1994. While the new guidelines are very similar to the interim guidelines, the final rule contains some important changes, particularly in the areas of personnel requirements and equipment standards. This article outlines modifications to the interim guidelines, with particular emphasis on requirements for radiologic technologists.

Breast Neoplasms↗
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Interventional radiology of the liver and pancreas.

Interventional radiology is a rapidly developing subspecialty that combines traditional imaging procedures with minimally invasive therapeutic procedures performed under radiologic guidance. Appropriate use of interventional radiology avoids surgery and eliminates the need for general anesthesia, thereby decreasing patient morbidity, length of hospitalization and cost. This article provides an overview of the development of interventional radiology as a subspecialty and discusses its role in the treatment of diseases of the liver, pancreas and biliary tract.

Biliary Tract Diseases↗
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Recent advances in breast cancer imaging.

Mammography is the best technique currently available for early detection of breast cancer, but it has limitations. Several new techniques are under investigation that may provide valuable complementary images. This article discusses some of the most promising adjuncts to film-screen mammography, including digital mammography, ultrasound of the breast, breast MR, scintimammography and sentinel node lymphoscintigraphy.

Breast↗